For most new parents, it's who gets up in the night that causes the most arguments.
But Kate and William have bigger fish to fry in their first few weeks as mum and dad, as a row has erupted over Prince George's birth certificate.
You see, dear old William put his occupation as Prince of the United Kingdom, and added Kate's as Princess of the United Kingdom when he registered Georgie's birth.
We thought that was rather fabulous, but others, it seems, did not.
You see Kate is officially known as the Duchess of Cambridge, and has never been referred to as a Princess. According to Clarence House and Kensington Palace (up until last week, anyway), Kate is not a Princess, but a Duchess.
Buckingham Palace spokesperson James Roscoe told the Express: "I will check further, but I'm getting the impression there are no hard and fast rules in this area."
Back in 2011, when Kate married Wills, a palace spokesperson said: "The Duchess of Cambridge would have been Her Royal Highness Princess William if she had not been given her new title, but it is not correct to say she is a Princess now."
Another aide, Paddy Harverson, added at the time: "You don't automatically become a Princess when you marry a Prince. She's not a Princess, though we're quite relaxed about it and realise some people will call her a Princess. We are not going to get upset about it."
That's cleared that up then.